[0.15.31] Bug reappeared: Pump not connecting to fluid wagon

[gexxo]

I encountered the bug again I last encountered in 0.15.23 (see the thread: viewtopic.php?f=11&t=50279). A train arrives at a station and the pumps simply don't connect to its fluid wagons (none of the four pumps connects).

The strange things here are:

1.) The bug did not appear for several hours of playing and also with 0.15.31 I played a long time before it appeared
2.) But once it appeared once, it appeared another time after only around two minutes!
3.) I didn't do anything in the sector of my base when the bug hit me, I was busy conquering new resources on the other side of the map. I didn't flip a switch, I didn't change a build there, I didn't add or remove any trains.
4.) The only things that happend during the time:
a) Bots were creating another part of my base and laying down rail tracks. It might be that the problem might be connected to this.
b) As I was conquering new terrains and placing new radars, I also ran into the "radar too weak bug" that I reported here: viewtopic.php?f=29&t=51187. Thus, it might have been the case that the base was not covered by radar when the train arrived. The issue might happen when a train arrives at a non-radar-covered station.
5.) As you see, I just have wild guesses why that appeared, because I cannot reproduce it by loading the last autosave before the train arrived. The bug simply does not repro then, so it seem to be dependent on some quite brittle conditions.
Too bad, replays are deactivated in this save (due to version bumps), so I cannot just watch the replay to see why the pumps don't connect .

So the only thing I have is the map at a state where the bug has already happened. I am standing next to a train station, at the station is a train with full fluid tanks and the pumps simply do not connect. I hope this suffices to investigate the bug. Here is the situation in the savegame:

Picture showing the bug

pump-bug-2.png (8.25 MiB) Viewed 3959 times

[Rseding91]

Is the train actually stopped at the train stop or is it waiting at the signal/in manual mode?

[gexxo]

Yes, the train stopped at the train stop. It is in automatic mode (and if you wait long enough, it will go on to its next station, screwing up my whole base by pumping the fluid into a tank for which it is not suited).
The first screenshot was unfortunately timed as it showed the signal in blue. Here is another one shownig that the train is indeed not waiting at the signal but is automatic at the station.

pump-bug-3.png (2.94 MiB) Viewed 3924 times

[posila]

The train is little bit out of alignment with the pumps. When I sent it to the station again, it stopped at correct position. I am not sure how that could happen. My guess would be a level of breaking force was researched while the train was breaking, but your research is in middle of breaking force 13, so the train would have to wait in the station for very long time if that happened.
I slightly increased tolerance of pump to fluid-wagon connection, so it connected when I reloaded the save. So hopefully you won't have this problem again in next relase, but I am still interested to figure out how come train didn't stop exactly in the station.

[steinio]

The train is little bit out of alignment with the pumps. When I sent it to the station again, it stopped at correct position. I am not sure how that could happen. My guess would be a level of breaking force was researched while the train was breaking, but your research is in middle of breaking force 13, so the train would have to wait in the station for very long time if that happened.
I slightly increased tolerance of pump to fluid-wagon connection, so it connected when I reloaded the save. So hopefully you won't have this problem again in next relase, but I am still interested to figure out how come train didn't stop exactly in the station.

Rounding issue *cough*

[Sicnarf]

Try extending the rail after the stop one more tile (In a straight line) or move the stop back a tile so it has one square of straight tile in front of it.
If part of a fluid tanker train is on a curve everything from that point back cannot connect to fluid pumps.

Found this out with an oil train config that was 30 units long I was trying to fold it up a bit for loading. The first 6 tanks were on a straight and loaded fine, however all the rest were after a bend and even the one's on perfectly straight sections and lined up correctly would not connect to a pump no matter what I tried.
I think what is happening to you here is due to braking force research you train is pushing a fraction beyond the stop and hitting the start of the curve which is why it won't hook up no matter what you do. Have one straight tile after the train stop and see if it fixes it.

[gexxo]

The train is little bit out of alignment with the pumps. When I sent it to the station again, it stopped at correct position. I am not sure how that could happen. My guess would be a level of breaking force was researched while the train was breaking, but your research is in middle of breaking force 13, so the train would have to wait in the station for very long time if that happened.
I slightly increased tolerance of pump to fluid-wagon connection, so it connected when I reloaded the save. So hopefully you won't have this problem again in next relase, but I am still interested to figure out how come train didn't stop exactly in the station.

It could indeed be the braking force. I don't know exactly anymore, but it might be that I researched braking force 12 before braking force 13 and I have a huge number of labs, so this could indeed have been the reason.

Could it be that the level of braking force I researched is too high in general for trains to brake at the exact position? Maybe I should not research more braking force?

@Sicnarf: If your theory was correct, then wouldn't all my tankers malfunction? But they don't, they seem to work most of the time.

[Sicnarf]

@Sicnarf: If your theory was correct, then wouldn't all my tankers malfunction? But they don't, they seem to work most of the time.

My theory would only apply to tanker stops where the very first tile after the stop is a curved rail like the one in your picture. Any stops with a straight rail directly after it would be unaffected.

[gexxo]

@Sicnarf: If your theory was correct, then wouldn't all my tankers malfunction? But they don't, they seem to work most of the time.

My theory would only apply to tanker stops where the very first tile after the stop is a curved rail like the one in your picture. Any stops with a straight rail directly after it would be unaffected.

Most of my stops are built like this and they worked fine for a few days game time .